Re: "No Balls"

: : : : Your understanding is correct--"a lack of courage".
: : : : Just a guess but I think the origin is quite sexist.
: : : : In the US women are discriminated against in jobs, pay and status. They are second class citizens to males.
: : : : The phrase is a reference to a woman's lack of a scrotum and, therefore, her lack of status since she does not have the ability to produce testosterone, that manly of all manly body chemicals.

: : : We can fix this. How about -- "You don't have the ovaries to do that." Or, if someone is cowardly, call him or her "t*tless." What do you think?

: : I think the metaphor arose from a comparison between men and little boys, not between men and women, and is based on external anatomy, not on endocrine physiology. This belief is totally intuitive. I have no evidence to back it up.

: I agree with R.Berg. It's rarely used towards woman. It is usually used towards men to demasculate them.

I suspect that it is as stated: 'No Balls" equals implied absence of testicles together with the testosterone which powers male recklessness, courage and aggression.